PY-17331 Consider "class" as reserved word in Python, not "__class__"

python/psi-api/src/com/jetbrains/python/PyNames.java

@@ -483,7 +483,7 @@ public class PyNames {
     EXCEPT,
     IMPORT,
     PRINT,
-    __CLASS__,
+    CLASS,
     EXEC,
     IN,
     RAISE,

python/testData/refactoring/introduceVariable/dontSuggestReservedName.py

@@ -0,0 +1,5 @@
+class Class:
+    pass
+
+
+Cl<caret>ass()

python/testSrc/com/jetbrains/python/refactoring/PyIntroduceVariableTest.java

@@ -87,6 +87,12 @@ public class PyIntroduceVariableTest extends PyIntroduceTestCase {
     assertDoesntContain(suggestions, "select");
   }
 
+  // PY-17331
+  public void testDontSuggestReservedName() {
+    final Collection<String> suggestions = buildSuggestions(PyCallExpression.class);
+    assertDoesntContain(suggestions, "class");
+  }
+
   public void testSuggestNamesNotInScope() {  // PY-4605
     final Collection<String> strings = buildSuggestions(PyExpression.class);
     assertTrue(strings.contains("myfunc1"));